曝气生物滤池对玉米青贮渗出液处理效果

为了考察曝气生物滤池(biological aerated filter,BAF)处理玉米青贮渗出液的效果及其影响因素,重点考察了水力负荷、气水比、有机负荷和滤床高度。结果表明:水力负荷从0.5m3/(m2.h)升高到3.0m3/(m2.h)过程中,化学需氧量(COD)和NH3-N的去除率先升高后降低,当水力负荷1.5m3/(m2.h)时COD和NH3-N的去除率分别达到最大为83.5%、74.9%;增加气水比使得系统中溶解氧充足,可明显提高COD和NH3-N去除率,当气水比为3.5:1时COD和NH3-N的去除率分别达到最大为87.5%、75.2%;低有机负荷不利于COD和NH3-N的去除,当有机负荷为COD2.4kg/(m3.d)时,COD和NH3-N去除率最低分别仅为49.6%、58.5%,有机负荷为COD4.8kg/(m3.d)时去除率最高分别可达80.9%和75.9%,但过高的有机负荷反而对NH3-N去除不利,当有机负荷为COD7.2kg/(m3.d)时,NH3-N去除率降低为61.7%;滤床高度对硝化反应去除NH3-N影响较大,NH3-N生物硝化反应去除行为主要发生在0.6～1.0m区域。试验表明采用BAF系统处理玉米青贮渗出液是可行的,也为类似性质废水处理和改善农村水环境质量提供有益的参考。     

添加硝化抑制剂DMPP对红壤水稻土硝化作用及微生物群落功能多样性的影响

通过室内培育试验,研究了不同施氮水平下添加硝化抑制剂(DMPP)处理对红壤水稻土NH4+-N、NO3–-N含量、微生物生物量碳及微生物群落功能多样性的影响。结果表明:56天培养期内,不同处理的NH4+-N含量总体呈下降趋势,而NO3–-N含量呈上升趋势。随施氮水平提高,培养期内NH4+-N平均含量从0 mg/kg处理的24.10 mg/kg增加到400 mg/kg处理的412.10 mg/kg,NO3–-N平均含量从0 mg/kg处理的41.88 mg/kg增加到400 mg/kg处理的99.83 mg/kg。添加DMPP显著抑制硝化作用进行,抑制效果随施氮量增加而提高,400 mg/kg施氮水平下,添加DMPP硝化率和硝化速率比不添加DMPP处理分别下降了29.0%和44.3%,下降幅度远大于其他施氮水平处理。施氮水平也影响土壤微生物生物量碳和微生物群落功能多样性。施氮量从0 mg/kg增加到400 mg/kg,土壤微生物生物量碳下降了12.5%,AWCD值下降了78.4%,Shannon指数下降了22.3%;与不添加DMPP处理相比,添加DMPP处理的土壤微生物生物量、AWCD值、Shannon指数分别提高了2.1%、23.9%、7.8%,尤其在400 mg/kg施氮水平下,提高的幅度更加明显。     

增设回流提高厌氧氨氧化反应器脱氮效能

采用2套上流式反应器接种厌氧氨氧化污泥,研究了高基质浓度下增设回流对厌氧氨氧化反应器脱氮性能影响.研究结果表明,增设出水回流的反应器1经过116 d的运行,进水NH4+-N和NO2--N质量浓度由初始100、130 mg/L达到602、782 mg/L时,出水质量浓度仅增加到44、60 mg/L,氮容积去除负荷最高达到7.87 kg/(m3·d).NO2--N与NH4+-N的转化比维持在1.303,NO3--N生成量与NH4+-N转化量之比维持在0.24.无回流的反应器2经过67 d运行,进水NH4+-N和NO2--N质量浓度由最初100、130 mg/L分别增加到456和600 mg/L,相应出水质量浓度达到174和253 mg/L,氮容积去除负荷最高达到4.31 kg/(m3·d).NO2--N与NH4+-N的转化比维持在1.298左右, NO3--N生成量与NH4+-N转化量之比维持在0.21.说明回流对进入反应器的基质具有较强稀释作用,有助于避免高基质浓度对厌氧氨氧化活性的影响,同时对厌氧氨氧化反应过程中氮素转化比不产生影响.增设出水回流后的反应器1污泥粒径主要分布在1.25~2 mm之间,而反应器2污泥粒径主要分布在0.9~1.6 mm.说明在反应器运行过程中增设回流有助于反应器内液体上升流速的增加,颗粒污泥具有良好的流态,能够更好地与底物接触,有利于微生物增长.     

三种氮肥对红壤硝化作用及酸化过程影响的研究

以安徽郎溪耕地红壤耕层土壤为对象,采用室内恒温培养方法,研究了CO(NH2)2、(NH4)2SO4及NH4HCO3 3种氮肥在不同施用量条件下对土壤硝化作用及酸化过程的影响。结果表明:对照处理土壤的净硝化速率为(NO2-+NO3-)-N 25.7 mol /(kg?d);3种化学氮肥添加到土壤后均显著促进了土壤的硝化作用,CO(NH2)2、NH4HCO3处理土壤的净硝化速率分别为(NO2-+NO3-)-N 51.3～189.6、50.7～149.9 mol /(kg?d),且净硝化速率随氮肥用量增加而增加;(NH4)2SO4处理土壤的净硝化速率为(NO2-+NO3-)-N 60.5～107.9 mol /(kg?d),以施用量N 150 mg /kg时最大。研究同时发现, 3种化学氮肥均导致土壤pH下降,CO(NH2)2、 NH4HCO3处理土壤pH较对照处理分别下降0.11～0.43、0.02～0.36 pH单位,氮肥施用越多,pH下降越大;(NH4)2SO4处理土壤pH较对照处理下降0.08～0.26 pH单位,以施用量N 150 mg /kg时下降最大, N 300 mg /kg时下降最小。统计分析表明,土壤pH与土壤中(NO2-+NO3-)-N含量呈极显著负相关,土壤酸化速率与净硝化速率有显著的线性相关关系,说明氮肥通过硝化作用影响土壤酸度。     

有机肥部分替代化肥对滴灌棉田氮素转化及不同形态氮含量的影响

在滴灌条件下,采用连续3年定位增施有机肥小区试验,研究了不同有机无机肥配比对滴灌棉田土壤铵态氮、硝态氮、微生物量氮、全氮以及土壤矿化和硝化特性的影响,旨在明确滴灌棉田增施有机肥条件下土壤氮素转化与各形态氮素特征。结果表明,增施有机肥各处理均可显著增加土壤NH+4-N和NO-3-N含量(P0.05),且明显增加NH+4-N占总氮(TN)比例。在各施肥处理中,以配施6 000 kg·hm-2生物有机肥处理(60%CF+BF2)的矿质氮含量最高;3年连续增施有机肥3 000~6 000 kg·hm-2可明显增加滴灌棉田全氮和微生物量氮含量(P0.05),其中生物有机肥(CF+BF)对提高微生物量氮(MBN)/TN的效果显著,其土壤全氮分别比对照(CK)和单施化肥处理(CF)提高了24.7%~37.1%和13.3%~24.5%,微生物量氮分别增加53.8%~98.5%和32.2%~70.5%。有机无机肥配施可明显提高土壤硝化势和矿化能力。土壤增施3 000~6 000 kg·hm-2有机肥对促进滴灌棉田氮素转化,调节不同形态氮素比例及提高氮素肥力有显著效应。     

适宜填料提高温室甲鱼养殖废水曝气生物滤池处理效能

温室甲鱼养殖废水的无序排放已成为长三角农村地区重要污染源之一,特别在温室甲鱼养殖密集区尤为明显。为了探索曝气生物滤池处理温室甲鱼养殖废水的可行性,并筛选适合于温室甲鱼养殖废水水质的生物滤池填料,为处理工艺的实际应用提供参考。该文以斜发沸石、生物陶粒和砾石等3种填料及以此作为填料的曝气生物滤池为研究对象,研究不同填料对温室甲鱼养殖废水N、P的吸附性能及其净化废水的效果。研究结果表明,3种填料的N吸附容量为0.469～0.563 mg/g,3种填料对N的吸附量差异不大（P>0.05）,P吸附容量0.003～0.114 mg/g,其中沸石对P的吸附量最高。在某典型温室甲鱼养殖场建立温室甲鱼养殖废水曝气生物滤池处理中试工程,经过122 d的运行,结果表明沸石、砾石和陶粒滤池对COD、NH4+-N、TN（总氮）以及TP（总磷）等污染物均具有良好的去除作用,整个运行过程中COD去除率59.4%～61.1%,NH4+-N去除率达93.2%～97.2%,TN去除率54.4%～71.1%,TP去除率为62.7%～84.3%,沸石滤池对TN去除作用最佳,砾石和陶粒滤池对TP的去除率较好。生物滤池对氮磷的去除是填料吸附和微生物共同作用的结果,填料种类对废水的处理效能影响较小,考虑到填料的成本和来源,砾石是曝气生物滤池处理温室甲鱼养殖废水时较为理想的填料。若在温室甲鱼养殖场位于环境敏感区,对氮的去除要求较高,则可采用沸石为填料。综上所述,曝气生物滤池处理工艺具有较高的推广应用价值,适合中国温室甲鱼养殖场废水的处理。     

不同浓度葡萄糖添加对黑土氨基酸转化的影响

通过室内培养方式,研究不同浓度葡萄糖与无机氮肥(NH4)2SO4配施对土壤微生物将无机态氮转化为氨基酸态氮过程的影响。结果表明:和单施(NH4)2SO4培养相比,葡萄糖与(NH4)2SO4配合施用显著提高了土壤微生物将无机态氮向氨基酸态氮转化的程度,高浓度葡萄糖的添加更有利于无机态氮的同化。同样培养条件下NH4+-N、NO3--N和微生物量氮的数据表明,添加碳源明显降低了土壤中NH4+-N和NO3--N的含量,而微生物量氮量明显提高。表明活性碳源的加入明显提高土壤微生物活性,起到调控土壤微生物将无机态N转化为氨基酸态氮速率和容量的作用。     

一株具有多途径氮代谢功能的荧光假单胞菌

为研究全自养脱氮过程，采用斯凯尔曼亚硝化单胞杆菌培养基，从南京某城市污水处理厂序批式处理系统（SBR）中分离得到一株具有多途径氮代谢功能的荧光假单胞菌Pseudomonas fluorescens dN13。该菌株在有氧条件下，无有机碳源存在，能进行氧化NH3-N产能代谢生长；有有机碳源存在且NO2^- -N和NO3^- -N的浓度较高时，它能将NO2^- -N和NO3^- -N还原为NH3-N。在厌氧条件下，只有乙酸钠作碳源时，该菌株仍能进行硝酸亚硝酸还原（反硝化）作用。在这个具有多途径氮代谢功能的菌株细胞内，硝化反硝化过程耦合成为可能。     

太湖地区稻麦轮作农田改葡萄园对土壤氮转化过程的影响

采用15N成对标记技术结合数值模型,测定太湖地区两种土地利用方式(稻麦轮作农田和葡萄园)下的土壤氮素初级转化速率,探讨了土地利用方式改变对土壤供氮和保氮能力的影响。结果表明,葡萄园土壤初级矿化速率高于稻麦轮作农田土壤,但是其NH4+-N同化速率几乎可以忽略不计(0.02 mg kg-1 d-1),自养硝化成为培养条件下葡萄园土壤NH4+-N的唯一去向。葡萄园土壤初级自养硝化速率(15.85 mg kg-1 d-1)显著高于稻麦轮作农田土壤(13.65 mg kg-1 d-1),但两者初级异养硝化速率和NO3--N同化速率均接近零值。可见,太湖地区稻麦轮作农田改种为葡萄园后,土壤NH4+-N同化速率显著降低而自养硝化速率增加,由此导致更多的NO3--N在土壤中累积,进而可能增加土壤中N的淋溶和径流损失风险。     

青弋江芜湖市段无机氮的分布特征

通过实地监测,系统分析青弋江芜湖市段三态无机氮的分布特征,研究表明:(1)青弋江芜湖市段无机氮无论是枯水期还是丰水期,NO3-N和NH4-N浓度从上游到下游不断上升,总体体现了NO2-N,NH4-N不断转化为NO3-N的过程.(2)无机氮分布具有明显的季节变化,总体桔水期含量较高,丰水期较低,说明氮污染物主要来源于市区点源排放,丰水期流量大,对污染物起到稀释的作用.(3)三态无机氮含量随叶绿素a的增加而减少,呈负相关.(4)青弋江芜湖市段DO含量较高,不会成为氮硝化反应的限制因素,有利于三氮之间的相互转化.     

猪瘟病毒生物学特性研究的一些新进展

本文综述了近年来对猪瘟病毒的生物学特性研究的一些新进展。许多研究表明 ,在抗原性、病原性、病理和遗传特性方面均显示出一致的多样性分布。在细胞培养特性方面 ,猪瘟病毒一般不能引起细胞病变 ,但研究者也培养出一种来源于猪贤的 FS L 3细胞系 ,接种猪瘟病毒后可引起细胞病变 ,对该病毒的进一步研究将非常有益     

Repeated applications of farmyard manure enhance resistance and resilience of soil biological functions against soil disinfection

The effect of repeated application of farmyard manure (FYM) on resistance and resilience of some of soil biological functions was compared between two soils [chemically fertilized soil (CF soil) and chemically and organically amended soil (CF+FYM-soil)]. The impact of chloropicrin and metam sodium disinfection on organic matter (glucose and chitin) decomposition activity and number of ammonia oxidizing bacteria in the soils was measured periodically from just after disinfection to evaluate stability of soil biological functions to soil disinfection. Glucose and chitin decomposition activity and number of ammonia oxidizing bacteria was suppressed by soil disinfection more seriously in the CF soil than in the CF+FYM soil. The decomposition rates recovered in the disinfected CF+FYM soil 2 to 12 weeks after disinfection, but not in the CF soil during 12 weeks incubation. These results demonstrated that soil resistance and resilience of the selected biological functions may be higher in the CF+ FYM soil than in the CF soil. The ratios of fungal and bacterial contribution to glucose decomposition activity were evaluated by the substrate-induced respiration method. Chloropicrin and metam sodium disinfection decreased fungal contribution throughout the incubation period (12 weeks) in the CF soil. A similar tendency was observed in the CF+FYM soil, but the fungal contribution tended to recover more rapidly in the CF+FYM soil than in the CF soil. Repeated applications of FYM may be an effective way to enhance soil functional stability.     

Impact of pyrochar and hydrochar on soybean (Glycine max L.) root nodulation and biological nitrogen fixation

The aim of this study was to identify effects of carbonized organic material (“biochar”) on soybean growth, root nodulation and biological nitrogen fixation, and to elucidate possible underlying mechanisms. Soybean (Glycine max L.) was grown in four arable soils amended with carbonized organic material produced from wood or maize as feedstocks, by pyrolysis (“pyrochar”) or hydrothermal carbonization (“hydrochar”). Nodulation by Bradyrhizobium , biological nitrogen fixation (BNF) assessed by ¹⁵N techniques, plant growth, nutrient uptake and changes in chemical soil properties after soil amendment were determined. Data were analyzed by means of a three way ANOVA on the factors soil, carbonization technique and feedstock. It turned out that soybean root nodulation and BNF was influenced by the carbonization technique used to prepare the soil amendment. Hydrochar, in average and across all soils, increased nodule dry matter and BNF by factors of 3.4 and 2.3, respectively, considerably more than pyrochar, which led to 1.8 and 1.2 fold increases, respectively. Nodule dry matter and BNF correlated positively with available soil sulfur and negatively with available soil nitrogen. Hydrochars provided more available sulfur than pyrochars, and hydrochars caused a decrease in nitrogen availability in the soil solution, thereby exerting a positive influence on nodulation and BNF. Pyrochar amendment increased soil pH but had no effect on nodulation and BNF. Plant growth was affected by the soil and by the feedstock used for the “biochar”, and increased slightly more in treatments with pyrochar and hydrochar made from maize, which was richer in nitrogen and potassium. The results show that carbonized organic materials, and specifically hydrochar, have the capacity to increase BNF in soils. We suggest that this enhancement in BNF in response to soil amendments with carbonized organic materials is due to an increase in available sulfur and a reduction of available soil nitrogen.     

A hierarchical framework for classifying seabed biodiversity with application to planning and managing Australia’s marine biological resources

A conceptual hierarchical framework for classifying marine biodiversity on the sea floor, used successfully for continental-scale bioregionalisation and adopted to guide marine resource planning and management in Australia, has wider application at a global scale. It differs from existing schemes for classifying marine biota by explicitly recognizing the overarching influence of large-scale biodiversity patterns at realm (ocean basin and tectonic), provincial (palaeohistorical) and bathomic (depth-related) levels. The classification consists of 10 nested levels within realms, of which the first seven are primarily spatially nested and ecosystem based, and the lowest levels represent units of taxonomic inheritance: 1 - provinces, 2 - bathomes, 3 - geomorphological units, 4 - primary biotopes, 5 - secondary biotopes, 6 - biological facies, 7 - micro-communities, 8 - species, 9 - populations, and 10 - genes. According to this scheme, marine biodiversity is characterised in a systematic way that captures the scale-dependence and hierarchical organization of the biota. Levels are defined with respect to their functional roles and spatial scales, in a manner that directly supports the incorporation of biodiversity information in regional-scale planning by highlighting centres of endemism, biodiversity richness and priority information needs. Whereas species are the fundamental units of biodiversity, biological facies are the smallest practical unit for conservation management at regional scales. In applying the framework we make extensive use of biological and physical surrogates because marine data sets, particularly those of the deep sea, are usually sparse and discontinuous. At each level of the hierarchy, attributes and surrogates are defined to reflect the scale and range of biogeographic and ecological processes that determine the spatial and temporal distribution of marine biodiversity. The Australian experience in applying this framework suggests that it provides a workable systematic basis for defining, managing and conserving biodiversity in the sea.     

(A)ngstr(o)m-Prescott系数选取对参考作物蒸散量的影响-以黄河中游站点为例

利用黄河中游三个站点近50a的气象资料,研究了(A)ngstr(o)m-Prescott系数不同取值对参考作物蒸散量的影响.结果显示,当ngstrm-Prescott系数as和bs分别相差56%和93%时,引起的ET0差异月值在0.6%～26.2%,年值在173.1～197.4mm(18.2%～21.9%).ngstrm-Prescott系数不同取值对ET0的影响程度随地点而变化,即随海拔和日照时数的增加,对ET0的影响程度相应增大.因此在高海拔和高辐射地区,应对ngstrm-Prescott系数进行校正.尽管FAO56 PM推荐的(A)ngstr(o)m-Prescott系数在世界各地广泛应用,但依据本文结果尚不能确定其在中国能否直接使用.随着辐射数据的不断积累,有必要对这些系数进一步研究、验证和校正.     

强度耕作对^137Cs、^210Pbex和有机质剖面分布的影响

很少有关于直接测定强度耕作侵蚀引起土壤退化过程的报道。我们的目的是确定应用137Cs和210Pbex直接定量评价耕作侵蚀对土壤有机质(SOM)坡面运移影响的可能性。我们在黄土高原陡坡耕地上进行了50次犁耕活动,并将与其相临的另一块陡坡耕地作为对照。在对照坡地不同坡位,137Cs浓度均匀分布于上部0～30cm土层,而210Pbex浓度在坡上部和坡中部随土层深度增加呈现线性递减,在坡下部呈指数函数递减。0～30cm土层中土壤有机质含量显著大于30cm深度以下土层,并在坡中部和坡下部呈现与210Pbex类似的土壤剖面分布特征。与对照坡地比较,50次犁耕活动导致坡上部、坡中部0～45cm土层的SOM含量分别降低了38%和47%,坡下部0～100cm土层中的SOM含量却提高了18%。坡上部土壤剖面中137Cs浓度的加权平均值从1.48Bq/kg降低到0.29Bq/kg,坡中部从2.53Bq/kg减少到0.33Bq/kg,坡下部从1.48Bq/kg提高到2.81Bq/kg。210Pbex浓度的剖面加权平均值在坡上部从27.71Bq/kg下降到6.15Bq/kg,在坡中部和坡下部分别从35.46Bq/kg和25.53Bq/kg降低到1.57Bq/kg和19.40Bq/kg。137Cs和210Pbex的剖面分布与SOM在p<0.001水平呈显著相关,相关系数R2值在对照坡地为0.81～0.86,在犁耕实验坡地为0.86～0.91。实验结果表明,环境放射性核素137Cs和210Pbex在黄     

厌氧/缺氧/好氧生物接触氧化处理低碳氮比污水的物料平衡

为了提高低碳氮比污水的治理效果,提出了厌氧/缺氧/好氧-生物接触氧化脱氮除磷工艺(anaerobic anoxic oxic-biological contact oxidation,A2/O-BCO),研究了该工艺处理生活污水的脱氮除磷性能,建立了该系统处理过程的碳(以化学需氧量计,chemical oxygen demand,COD)、氮、磷的物料衡算公式,同时分析评价了不同硝化液回流比(100%,200%,300%,400%)下各指标的物料平衡情况。结果表明,该工艺在充分利用原水碳源、深度脱氮除磷方面具有较强的优势,系统COD主要在A2/O中厌氧段被利用,通过反硝化聚磷菌反硝化除磷脱氮;系统COD的物料衡算公式平衡百分比分别为96.4%、99.6%、98.7%和98.3%,氮的物料衡算公式平衡百分比分别为99.7%、98.2%、99.2%和96.5%,磷的物料衡算公式平衡百分比分别为92.0%、98.1%、93.3%和90.4%;荧光原位杂交表明生物膜中有厌氧氨氧化菌存在,且其数量占全菌比例的0.6%~2.7%,生物接触氧化的氮损失可能是由于发生了厌氧氨氧化反应;在硝化液回流比为300%时,系统氮、磷去除效果最好,出水达到国家城镇污水处理厂污染物排放标准一级A标准。该研究有助于更好地理解和分析工艺系统有机物、氮和磷的分布及变化情况,并且为评价试验数据的可靠性以及数学模型的建立提供了理论依据和指导,能更好地推广到分散型、量小且日变化系数较大的农村生活污水的治理事业中。     

Arbuscular mycorrhizae in a long-term field trial comparing low-input (organic, biological) and high-input (conventional) farming systems in a crop rotation

 Arbuscular mycorrhizal (AM) root colonization was studied in a long-term field trial in which four farming systems currently in use in Switzerland were continuously applied to a randomized set of plots at a single field site from 1978 till 1993. There were two low-input farming systems (organic and bio-dynamic) and two high-input (conventional) farming systems (according to Swiss guidelines of integrated plant production with and without farmyard manure). The systems had an identical 7-year crop rotation and tillage scheme and differed essentially only in the amount and type of fertilizer supplied and in plant protection management. The percentage of root colonization by AM fungi was determined in field samples 2–3 times over the growing season in crops in the rotation, namely in winter wheat (Triticum aestivum L. cv. Sardona), vetch-rye and grass-clover. We found the percentage of root length colonized by AM fungi to be 30–60% higher (P≤0.05) in the plants grown in soils from the low-input farming systems than in those grown in conventionally farmed soils. Approximately 50% of the variation of AM root colonization was explained by chemical properties of the soils (pH, soluble P and K, exchangeable Mg), the effect of soluble soil P being most pronounced. The potential of the field soils from the differently managed plots to cause symbiosis with AM fungi was tested in a glasshouse experiment, using wheat as a host plant. Soils from the low-input farming systems had a greatly enhanced capacity to initiate AM symbiosis. The relative differences in this capacity remained similar when propagules of the AM fungus Glomus mosseae were experimentally added to the soils, although overall root colonization by AM fungi was 2.8 times higher. Received: 27 August 1999     

农杆菌介导法获得大量转双价抗虫基因水稻植株

构建含Bt杀虫基因cryIA(c)和豇豆胰蛋白酶抑制剂基因CpTI的双价抗虫转基因载体PCAM-Bt-CpTI，并用于农杆菌（Agrobacterium tumefaciens)介导法对粳稻品系“浙大19”遗传转化，约2000块盾片愈伤组织与农杆菌共培养后，得到了约1300块潮霉素抗性愈伤，从中分化抗性再生苗约1500株，对不同抗性愈伤来源的70个T0代再生株进行PCR及PCR-Southern检测，62株为转cryLA(c)和CpTI双价抗虫基因植株，阳性植株比例为88.6%，抗虫鉴定表明，3个转基因T1代株系对二化螟有很高的毒性。